1. Field of the Invention
The present invention relates in general to low-noise optical probes which use optical energy to determine the characteristics of a medium, and in particular to optical probes having flexible, secure connectors for communicating signals to and from the probe.
2. Description of the Related Art
Electromagnetic, light or acoustic signals with known characteristics, when transmitted through or reflected in a medium, may reveal important information about that medium. In the field of medical testing and diagnosis, for example, light, heat or sound signals may be directed at a patient, transmitted or reflected through the patient""s body, and received and compared with the original signal or wave. As a result, information about the patient""s condition can be deduced without invasive testing, and information can be gathered continuously with minimal patient discomfort. For example, during surgery, blood oxygen saturation can non-invasively be deduced and continuously monitored.
Typically, reusable and disposable optical probes are employed to measure an amount of transmitted or reflected light through an accessible part of the body, such as a finger, an earlobe, loose skin, a forehead, or the like. For example, reusable and disposable optical probes or sensors having the foregoing characteristics are disclosed and described in U.S. Pat. No. 5,782,757.
The foregoing sensors typically incorporate a light source such as a lightemitting diode (LED) placed on one side of the body part, and a photodetector placed on an opposite side of the body part. The sensor may also connect to external monitoring equipment through a wire or cable. For example, reusable sensors often connect to external monitoring equipment through a permanent, plastic molded connection between the sensor and the cable.
The foregoing sensors suffer from at least several drawbacks. For example, the sensor is often limited to the useful life of the permanent plastic molded wire in that when the wire fails, the sensor is rendered inoperable despite its continuing functionality. Likewise, when the sensor fails, the wire or cable, the cost of which may not be trivial, is also rendered useless. In addition, existing reusable sensors do not have the capability to connect to monitoring equipment in a secure, reusable, yet flexible manner.
Based on at least the foregoing, there is a present need for an optical probe or having an electrical connector designed to connect the sensor to external monitoring equipment in a secure, reusable, yet flexible manner. According to one embodiment, the optical probe is usable with a patient cable connector designed to engage disposable or reusable/disposable (resposable) optical probes.
In one aspect of the invention, an improved optical probe assembly is disclosed which incorporates an electrical connector. The electrical connector includes a flexible plastic tab, on which is placed a flexible circuit. The plastic tab and circuit are typically at least partially enclosed in a protective housing. A separate patient cable connector attaches to the electrical connector via the flexible plastic tab, and a wire or other communications link connects the patient cable connector to external monitoring equipment. According to one embodiment, the electrical connector mates the patient cable connector in a manner that prevents incorrect engagement that may damage portions of the optical probe or patient cable connector.
In another aspect of the invention, an improved optical probe is disclosed having an electrical connector. According to one embodiment, once the patient cable connector has been connected to the electrical connector, the flexible plastic tab is locked into place within the patient cable connector via a locking aperture on the flexible plastic tab. The resulting connection is flexible, but electrically secure.
In another aspect of the invention, an improved optical probe assembly is disclosed with an electrical connector designed to accept connections to various external monitoring equipment and may accept connections using various types of wires. Thus, the patient cable connector may be connected to, for example, a wireless transmitter and/or battery, eliminating the need for a wire at all. Additionally, the type of wire may be varied based on patient needs, and the replacement of wires and patient cable connector may take place separately as needed from the replacement of optical probes.
In another aspect of the invention, an improved optical probe assembly is disclosed having an electrical connector adaptable for use with patient cable connectors designed for disposable, reusable, durable, and combination reusable/disposable sensors. Through the use of a standardized or universal patient cable connectors, optical sensors are advantageously used interchangeably and easily adapted to different monitoring equipment and patient conditions.
In another aspect of the invention, an improved optical probe assembly is disclosed with an electrical connector which is protected from fluids and the environment surrounding the sensor. Additionally, both a patient cable connector and protective housing over the electrical connector include shielding to prevent leakage of electromagnetic radiation which otherwise might interfere with operation of the optical probe.
In yet another aspect of the invention, an improved optical probe is disclosed with an electrical connector. The optical probe includes an improved pivoting mechanism around the finger such that the internal geometry of the light source, finger material, and photodetector are subject to less variation from finger movement. In addition, the optical probe provides more consistent pressure on the finger throughout the mechanism, uses fewer parts, includes a more straightforward assembly, and is less expensive to achieve appropriate geometry and pressure results.
Therefore, an aspect of the invention is an optical probe for irradiating tissue and producing a signal indicative of a physiological parameter of the tissue. The optical probe comprises a housing substantially securing a light source and a detector to tissue at a measurement site, thereby allowing the detector to produce a signal indicative of at least one physiological parameter of the tissue. The optical probe also comprises a plugable electrical connector forming a releasable connection with a cable connector, wherein the electrical connector includes a plurality of conductive paths electrically communicating with the light source and the detector. The cable connector electrically communicates with external monitoring equipment.
Another aspect of the invention is a reusable pulse oximetry sensor for producing a signal indicative of at least one physiological parameter of tissue. The sensor comprises an upper housing having a first circuit element comprising one of a light source and detector, and a first wire connected to the first circuit element. The sensor also comprises a lower housing having a second circuit element comprising the other of the light source and the detector, and a second wire connected the second circuit element. The sensor also comprises a hinge-like joint adjustably coupling the upper housing and lower housing and an electrical connector having a tab and a flexible circuit mounted on the tab and comprising a plurality of conductive paths. One of the conductive paths electrically connects to the first wire while another of the conductive paths electrically connects to the second wire, thereby providing an electrical connection from the conductive paths of the electrical connector to the light source and the detector.
Another aspect of the invention is a reusable pulse oximetry sensor for producing a signal indicative of at least one physiological parameter of tissue. The sensor comprises an upper housing having a first circuit element comprising one of a light source and a detector, and a lower housing having a second circuit element comprising the other of the light source and the detector. The sensor also comprises a hinge-like joint adjustably coupling the upper housing and lower housing, and an electrical connector having a tab, and a flexible circuit mounted on the tab and comprising a plurality of conductive paths. One of the conductive paths electrically connects to the detector while another of the conductive paths electrically connects to the light source.
Another aspect of the invention is an optical probe for non-invasively collecting a signal indicative of a physiological parameter of tissue. The optical probe comprises a light source, a detector, a connector having a flexible circuit mounted on a durable tab, and a protective housing at least partially covering the flexible circuit mounted on the durable tab.
Another aspect of the invention is a method of determining a physiological parameter of tissue using a non-invasive optical probe. The method comprises positioning a light source of a non-invasive optical probe to irradiate a measurement site with light, and positioning a detector of the probe to detect light which interacts with the measurement site. The method also comprises releasably connecting an external monitoring equipment cable to the probe through a flexible circuit mounted on a durable tab having a protective cover. Also, at least one the conductive paths electrically communicates with the light source and at least one of the conductive paths electrically communicates with the detector.
Another aspect of the invention is an electrical connector, comprising a flexible durable tab configured to guide a cable connector around the tab, thereby engaging the electrical connector to the cable connector. The connector also comprises a flexible circuit mounted on the flexible tab and electrically communicating with electrical contacts of the cable connector. The connector also comprises a locking mechanism releasably locking the electrical connector to the cable connector, and a protective cover covering at least a portion of the flexible circuit.
For purposes of summarizing the invention, certain aspects, advantages and novel features of the invention have been described herein. Of course, it is to be understood that not necessarily all such aspects, advantages or features will be embodied in any particular embodiment of the invention.